Hydrogen under pressure

C, b.p. 16UC. Manufactured by heating phenol with hydrogen under pressure in the presence of suitable catalysts. Oxidized to adipic acid (main use as intermediate for nylon production) dehydrogenated to cyclohexanone. 

C. It occurs in natural gas. May prepared by reduction of ethene or ethyne by hydrogen under pressure in the presence of a nickel catalyst, or by the electrolysis of a solution of potassium elhanoate. It has the general properties of the paraffins. Used in low-temperature refrigeration plant. 

Cobalt has an odd number of electrons, and does not form a simple carbonyl in oxidation state 0. However, carbonyls of formulae Co2(CO)g, Co4(CO)i2 and CoJCO),6 are known reduction of these by an alkali metal dissolved in liquid ammonia (p. 126) gives the ion [Co(CO)4] ". Both Co2(CO)g and [Co(CO)4]" are important as catalysts for organic syntheses. In the so-called oxo reaction, where an alkene reacts with carbon monoxide and hydrogen, under pressure, to give an aldehyde, dicobalt octacarbonyl is used as catalyst ... 

Trimethylene dibromide (Section 111,35) is easily prepared from commercial trimethj lene glycol, whilst hexamethylene dibromide (1 O dibromohexane) is obtained by the red P - Br reaction upon the glycol 1 6-hexanediol is prepared by the reduction of diethyl adipate (sodium and alcohol lithium aluminium hydride or copper-chromium oxide and hydrogen under pressure). Penta-methylene dibromide (1 5-dibromopentane) is readily produced by the red P-Brj method from the commercially available 1 5 pentanediol or tetra-hydropyran (Section 111,37). Pentamethylene dibromide is also formed by the action of phosphorus pentabromide upon benzoyl piperidine (I) (from benzoyl chloride and piperidine) ... 

P-Phenylethylamine is conveniently prepared by the hydrogenation under pressure of benzyl cyanide with Raney nickel catalyst (see Section VI,5) in the presence of either a saturated solution of dry ammonia in anhydrous methyl alcohol or of liquid ammonia the latter are added to suppress the formation of the secondary amine, di- P phenylethylamine ... 

Isomerization of sorbitol, D-mannitol, L-iditol, and dulcitol occurs in aqueous solution in the presence of hydrogen under pressure and a nickel—kieselguhr catalyst at 130—190°C (160). In the case of the first three, a quasiequiUbrium composition is obtained regardless of starting material. Equilibrium concentrations are 41.4% sorbitol, 31.5% D-mannitol, 26.5% L-iditol, and 0.6% dulcitol. In the presence of the same catalyst, the isohexides estabUsh an equihbrium at 220—240°C and 15.2 MPa (150 atm) of hydrogen pressure, having the composition 57% isoidide, 36% isosorbide, and 7% isomannide (161). 

Carbonylation by CO Exchange. A few metal carbonyls can be prepared by exchange of CO molecules. The reaction of WCl and Fe(CO) in the presence of hydrogen under pressure in diethyl ether results in yields of W(CO) as high as 85% (114). The same reaction can be used to... 

From ethyl laurate by reduction with hydrogen under pressure with copper catalyst. Ger. pat. 552,888 [C. A. 26, 5573 (1932)]-... 

Erythroidine behaves as a lactone and when one of its salts with an alkali or alkaline earth metal is catalytically hydrogenated under pressure, a mixture of dihydro-j3-erythroidines, with two tetrahydro- compounds is produced, from which dihydro- -erythroidine can be isolated as the hydrobromide. The dihydro- base has m.p. 85-6° (dec.), + 102-5° and... 

In a hydrogenation autoclave are introduced 92 g of 2-hydroxy-4-nitrophenylbenzoate preceded by 200 cc of ethyl acetate Raney nickel, obtained from 30 g of alloy, is added with 300 cc of ethyl acetate. Hydrogenation under pressure (100 to 120 kg) at ordinary temperature is carried out during a period of about 12 hours. The nickel is filtered off and the ethyl acetate is removed by distillation on the water bath under a vacuum of 300 mm. There is thus obtained 80 g of crude damp 2-hydroxy-4-aminophenylbenzoate which after recrystallization from isopropyl alcohol melts at 153°C. 

Hydrogenation has found commercial application in the conversion of liquid to solid fats. Vegetable oils contain a relatively high proportion of double bonds. Treatment with hydrogen under pressure in the presence of a catalyst converts double bonds to single bonds and produces solids such as margarine. 

T-4)-J or Raney nickel and hydrogen.8 Alcohols of the benzylic type have also been reduced directly with hydrogen under pressure in the presence of various catalysts,9 and benzoic acids have been reduced to toluenes with rhenium-type catalysts and hydrogen at high temperatures and pressures.10... 

Some reactions, such as the explosive reaction of hydrogen and oxygen, appear to proceed to completion, but others seem to stop at an early stage. For example, consider the reaction that took place when Haber heated nitrogen and hydrogen under pressure in the presence of a small amount of the metal osmium ... 

The following account refers primarily to commercial apparatus suitable for conducting hydrogenations under pressure the apparatus can, of course, be employed for other reactions under high pressures, but slight modifications of experimental procedure will probably be necessary. 

L. I. Class, Present State of Knowledge in Respect to the Properties of Steels Resistant to Hydrogen Under Pressure, Stahl and Eisen, August 18, 1960, Vol. 80, pp. 1117-1135. 

In an approach toward a synthesis of tetraponerine 37, Gevorgyan first synthesized the fully aromatic tricyclic system 49 and then reduced it over two steps, first via hydrogenation under pressure (50 psi) to give 36 followed by a second reduction by lithium aluminium hydride of the amidinium salt (Scheme 1) <2002OL4697, 2004JOC5638>. 

Another explosion phenomenon encountered in the storage of liquefied hydrogen under pressure is the BLEVE, which occurs from the sudden release of a large mass of pressurized... 

Chloroff A process for removing chlorine from organic chlorides such as polychlorinated biphenyls by reaction with hydrogen under pressure, over a proprietary catalyst. Developed by Kinetics Technology International. See also Hi-ChlorofiF. 

Milling atmosphere, which is a neutral protective gas (helium or argon) during mechanical milling or hydrogen under pressure up to 0.9 MPa under reactive mechanical alloying processes. 

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